Color television systems, as originally introduced, used a panchromatic or black-and-white light sensing tube together with a color wheel synchronized to the field rate then in use for monochrome. This color system had the major disadvantages that (a) the receivers depended upon visual persistence of the color image over three sequential fields, and (b) the receivers required that a large color wheel be synchronized with the received field rate. These problems might have been overcome with improved technology, but the adoption in 1953 of the current compatible color system and subcarrier standards, and the introduction of the shadow-mask color kinescope, and later of trinitron, eliminated interest in sequential color systems.
For many years, color television cameras used three vacuum-tube light sensors, together with light-splitting arrangements which separated light incident from the scene being televised into red, green, and blue components, or into their complementary colors cyan, magenta and yellow. These vacuum-tube sensors included such panchromatic devices as iconoscopes, image orthicons, and vidicons. The sensors included a light-sensitive screen, and arrangements for producing line-scan signals representative of the light pattern falling onto the screen. More recently, solid-state light sensor arrays such as charge-coupled device (CCD) arrays have been introduced. The CCD sensors have no inherent degradation with time, and are rugged, small and lightweight by comparison with their vacuum-tube counterparts, and can be made to produce line-scan signals similar to those produced by the vacuum-tube devices. These devices initially replaced the image tubes in portable cameras, but are now starting to replace the vacuum image tubes in studio cameras. For home color camcorder use, a single CCD imager is desirable for cost reasons. A single CCD imager with a color wheel is described in U.S. Pat. No. 4,471,388, issued Sep. 11, 1984 in the name of Dischert. This suggestion does not appear to have resulted in any actual use. Single-CCD arrangements using patterned color filters over the CCD imager, such as the stripe filters described, for example, in U.S. Pat. No. 4,437,764, issued Mar. 20, 1984 in the name of Levine et al., have found use for home camcorders. Various checkerboard color filter patterns have also been described, but these filters tend to degrade the color response of a CCD imager, because elements responsive to particular colors are widely separated and may result in aliasing, and these schemes also require the color filters to be correctly registered with the CCD sensor elements to prevent further degradation. The CCD color sensor for higher-performance applications may include a plurality of color-splitting prisms and CCD imagers bonded together into a single rugged, nonadjustable package, as described in U.S. Pat. No. 4,323,918, issued Apr. 6, 1982, and in U.S. Pat. No. 4,507,679, issued Mar. 26, 1985, both in the name of Bendell.
Improved television cameras or imagers are desired.